U.S. Route 19 Alternate (Florida)

U.S. Highway 19 Alternate (US 19 Alt.) is a 37.114 mi former section of US 19 from St. Petersburg to Holiday, Florida.

Beginning at the intersection of 4th Street North (US 92 and State Road 687 (SR 687) and 5th Avenue North in St. Petersburg, it runs west of US 19 near the Gulf coast passing through the cities of Seminole, Clearwater, Dunedin, and Tarpon Springs before ending at US 19 in Holiday, Pasco County. It is also the unsigned State Road 595 (SR 595) throughout the entire route. It also runs along much of the Pinellas Trail.

History
US 19 Alt. was established in 1951 when US 19 was realigned from St. Petersburg through Holiday. It hugs the Gulf coast, servicing Seminole, Clearwater, Dunedin, and Tarpon Springs before ending at US 19 in Holiday. Originally, the southern terminus of US 19 Alt. was at US 92/SR 687 in downtown St. Petersburg but was truncated to US 19 in St. Petersburg.

As of September 2007, however, signage indicates that US 19 Alt. once again follows US 19's old route all the way to US 92; this original route was numbered and signed as the hidden SR 595 designation of the main route, but the signs are slowly being phased out in favor of US 19 Alt. shields. Both shields are in current use, however, for the time being, with the US 19 Alt. signage on the highway itself, and the SR 595 directional signage at the intersections, including Interstate 275 (I-275) exit 23.

Realignment in Clearwater–Largo
Prior to February 2007, US 19 Alt. originally went south through downtown Clearwater on Fort Harrison Avenue, which becomes Clearwater–Largo Road upon entering Largo. It then turned east along West Bay Drive to the intersection of Seminole Boulevard, then turned south. This intersection is also the western terminus of SR 686 and, until the reconfiguration, the southern terminus of SR 651.

As of February 2007, US 19 Alt. was realigned along Missouri Avenue, directly north to SR 60 (Court/Chestnut streets) in Clearwater, west to Myrtle Avenue, then north, before joining Fort Harrison Avenue south of Sunset Point Road. The new alignment now effectively bypasses the downtowns of Largo and Clearwater. The original alignment has since been decommissioned by the Florida Department of Transportation (FDOT) and transferred to the cities of Largo and Clearwater. SR 651 is used in FDOT's road inventory lists concurrent with the US 19 Alt. alignment.

When this plan was first announced in 2001, it was viewed as good news for commuters and businesses championing the project as a way to turn Clearwater into a walkable community.

Proposed expressways
The planned St. Petersburg–Clearwater Expressway, or Pinellas Beltway, proposed in 1974, would have followed the current alignment of US 19 Alt. from I-275 to Clearwater. A freeway revolt canceled the beltway by 1980. The intersection of Seminole and Bay Pines boulevards at SR 666 is a remnant of this proposed road.

State Road 595 and County Road 595
Two extensions of hidden SR 595 exist beyond US 19 Alt. The first one is between US 19 and US 92 in downtown St. Petersburg, though this is being phased out, as signage indicates that US 19 Alt. now ends at US 92 instead of US 19. The other is a brief multiplex with US 19 in Holiday which terminates a block north of the northern terminus of US 19 Alt. in Holiday at Mile Stretch Road. County Road 595 (CR 595) consists of Mile Stretch Road, then takes a sharp left onto Grand Boulevard. Within Holiday and Elfers, the road runs along the right-of-way of a former railroad line before heading to Main Street in New Port Richey, where it secretly makes another left turn before terminating at US 19. CR 595 can be found again between Hudson and Aripeka, where it crosses the Pasco–Hernando county line along the Gulf of Mexico on its way toward Hernando Beach, only to bypass downtown Hernando Beach and terminate once again with US 19, but this time also with the western terminus of CR 574/Spring Hill Drive.